The development of linear referencing systems (LRS) continues to be a primary effort at Department of Transportations around the world, and the FGDC is developing a NSDI Framework Transportation Identification Standard model for routes.A LRS CD containing research papers is available from the US Bureau of Transportation Statistics and standards for LRS functional requirements are emerging.
Several desktop GIS packages offer linear referencing related capabilities.This article summarizes Maps in the Fast Lane - Linear Referencing and Dynamic Segmentation appearing in GISVision online magazine December 1, 2001 issue.
|ESRI , Inc., Redlands, CA|
ESRI's new, ArcGIS Desktop family of products includes ArcView 8, ArcEditor 8 and ArcInfo 8.Highend ArcInfo comes with thirty-five command line driven tools related to dynamic segmentation.ArcGIS introduces the geodatabase, which supports a new model for the dynamic segmentation route system in all three products called the "Polyline with Measures" feature class.ArcGIS 8.02 included the API for accessing PolylineM features.The June 2001 release of ArcGIS 8.1 features several DynSeg out-of-the-box analysis tools for events with from and to locations.
|Caliper Corporation, Newton, MA|
TransCAD is a GIS designed to store, display, manage, and analyze transportation data.Its tools for working with data that use a LRS are a direct extension of TransCAD route sytems.Event data, referred to as mileposts, can be point or line layers and can be displayed on top of routes, or to the right or left of centerline and used to create strip carts showing the varying characteristics of a route along its length.A point layer with coordinates can be converted to route/milepost format using the Add Mileposts command.
|Transportation, Transportation Analyst|
|Intergraph Corporation, Huntsville, AL|
Intergraph recently introduced two new products.GeoMedia Transportation adds dynamic segmentation capabilities to GeoMedia Professional including the ability to validate a network without first building special topology files.GeoMedia Transportation performs validation and dynamic segmentation on exposed feature sets that the user can create and modify as needed since topology is generated on the fly.A route can be identified by up to four keys associating it with event table records.Measure, measure with internal markers, measure with external markers, duration, duration with internal markers, and duration with external markers are all supported
|LRSx GeoMedia Client|
|TransDecisions, Inc., Boston, MA|
TransDecisions, Inc.'s Linear Referencing System Extensions (LRSx) provide an integrated set of functions and procedures for organizing, retrieving, and validating linear referenced data, while taking advantage of Oracle's security, recovery, reliability, scalability, and performance features.The LRSx Extensions are written entirely in Java, and feature an open and layered architecture integrated into the Oracle8i database server.The LRSx GeoMedia Client extends LRSx to Intergraph's GeoMedia and GeoMedia Professional software systems.ESRI support for LRSx is coming in 2001 Q4 with a LRSx ArcView 3 client and in 2002 Q1 for ArcGIS Desktop client.